The present invention relates to a cooking appliance, such as a cooker or a built-in hob unit.
It also relates to a gas burner for such a cooking appliance and to a method for mounting such a burner on such appliance.
Cooking appliances are known which comprise several cooking devices distributed over a cooking hob, for example gas burners and/or electric hotplates.
Conventional gas burners comprise, in particular, a gas injector, generally placed below the cooking hob surface, and a burner head, which emerges above the cooking hob surface. The gas is conveyed in a convergent-divergent system, of the venturi tube type which can, in particular, be a horizontal venturi or a radial venturi.
These known burners can also carry accessories, such as for example a spark ignition device, or a safety device such as a thermocouple designed to control a cut off of the gas supply when the burner flame is extinguished.
The head of the burner conventionally comprises several elements, including a burner body and a cover.
A flame distributor ring forms part of the head of the burner. It is, depending on the case, integral with the burner body or with the cover, or sometimes with an intermediate element which is positioned between the body and the cover.
The burners of the prior art have flame outlet orifices distributed along a peripheral line of the flame distributor ring, said orifices constituting the outer end of ducts formed in the ring for the delivery of the fuel mixture.
The delivery ducts of the known burners are directed radially outwardly, starting from a central point of the burner, and emerge on the periphery of the flame distributor ring. When the peripheral line of the ring is circular, the longitudinal direction of the ducts is normal to said peripheral line.
In operation, these burners supply flames which radiate radially outside of the burner, the points of the flames are inscribed in a perimeter which is substantially concentric with the perimeter defined by the peripheral line of the flame distributor ring.
If it is desired to increase the power of the burner, the flow rate of gas injected into the burner is increased. This necessitates, in order for the combustion to take place suitably, increasing the diameter of the burner head in order to increase the number of flames, and/or increasing the length of the said flames.
However, such burners would no longer pass the fabric ignition test, which consists in placing pieces of fabric near to a vessel of standardized dimensions placed above an ignited burner, in order to simulate the sleeves of the clothing of a user placed facing the front of the cooking appliance.
Because at powers greater than the maximum powers achieved at present by conventional burners, the latter produce flames which protrude from under the bottom of standardized vessels, they present a risk of igniting fabrics.
The risk becomes even greater as the burner becomes closer to the user, that is to say if the burner is positioned at the front of the appliance.
A first object of the invention is to propose a cooking appliance comprising at least one gas burner whose maximum power is sufficiently high to meet the current needs of users, while complying with the conditions imposed by the fabric ignition safety standards.